Warming winters have allowed mountain pine beetle outbreaks in the coldest areas of the western United States, but milder winters can't be blamed for the full extent of recent outbreaks in the region, a Dartmouth ...

Winter

Winter is one of the four seasons of temperate zones. Winter officially begins on the winter solstice, being the day of the year which has fewest hours of daylight. Winter ends, and spring begins, on the following equinox. In the Northern Hemisphere, depending on the year, this corresponds to the period between December 20 and 21 and March 20 or 21. Winter is the season between autumn and spring. In many countries in the Southern Hemisphere, including Australia , New Zealand and South Africa, winter begins on 1 June and ends on 31 August.

From a meteorological perspective, winter is the season with the shortest days and the lowest average temperatures. It has colder weather and, especially in the higher latitudes or altitudes, snow and ice. The coldest average temperatures of the season are typically experienced in January in the Northern Hemisphere and in June or July in the Southern Hemisphere.